Breaking up lengthy ShControlThread::run_service() method, moving setup, prepare and execute GC into separate methods. The patch should not have functional differences. Webrev: http://cr.openjdk.java.net/~zgu/shenandoah/cleanup_ctrl_thr/webrev.00/index.html Test: tier3_gc_shenandoah (release and fastdebug) Thanks, -Zhengyu